EEMOTE CONTROLLED LINE CONCENTRATOR 



281 



In this way, the number of the line which originated a service request is 

 locked into these counters until the bi-stable circuit is restored to nor- 

 mal. 



The HGT bi-stable circuit of Fig. 25 indicates which particular con- 

 centrator has originated a service request. A relay in the collector cir- 

 cuit has contacts which pass this information on to the other central 

 office control circuits to indicate the number of the concentrator on the 

 frame which is requesting service. This is the same as a horizontal group 

 on a regular line link frame and hence the horizontal group designation 

 is used to identify a concentrator. 



With the operation of this relay, relays associated with the counters 

 of the originating line number register are operated. These relays indicate 

 to the other central office circuits the vertical file and vertical group 

 identification of the calling line. Contacts on the vertical group relays 

 are used to set a bi-stable circuit associated with lead RL of Fig. 25 each 

 time the scanner pulse generator generates a pulse corresponding to the 

 vertical file of the calling line number registered. 



The operation of the HGT bi-stable circuit inhibits in the concentra- 

 tor control trunk circuit (Fig. 27) the transmission of further VG and 



SRS 



FROM 

 CONCENTRATOR 



CONTROL 

 TRUNK CIRCUIT 



RB 

 RH 



RH 



FROM 

 SCANNER 



PULSE 

 GENERATOR 



VF 



VFO-4 

 VG 



RS 



1 



*" 5-STAGE COUNTER ^ 



12-STAGE COUNTER 



^ ^ 



Fig. 26 — Originating line number register. 



